java客戶端與伺服器通信

A. java網路編程應該怎樣在客戶端和伺服器間實現通信

以前寫的，照貼了。。。伺服器端：import java.awt.*;x0dx0aimport java.awt.event.WindowAdapter;x0dx0aimport java.awt.event.WindowEvent;x0dx0aimport java.io.*;x0dx0aimport java.net.*;/*6、 採用UDP協議，編寫一個Java網路應用程序，該應用分伺服器端程序和客戶端程序兩部分。x0dx0a* 客戶端指定一個伺服器上的文件名，讓伺服器發回該文件的內容，或者提示文件不存在。x0dx0a* （20分）（服務端程序和客戶端程序分別命名為Server.java和Client.java）*/x0dx0apublic class N4BT6 extends Framex0dx0a{x0dx0aDatagramSocket socket ;x0dx0aDatagramPacket packet ;byte[] buf ;x0dx0aFile file ;x0dx0aFileInputStream input;x0dx0aString message = "該文件不存在";x0dx0aTextArea text;x0dx0apublic N4BT6(String title)x0dx0a{x0dx0asuper(title);x0dx0atext = new TextArea(6,4);x0dx0aadd(text);x0dx0asetSize(400, 300);x0dx0asetVisible(true);x0dx0aaddWindowListener(new WindowAdapter()x0dx0a{x0dx0apublic void windowClosing(WindowEvent e)x0dx0a{x0dx0adispose();x0dx0a}x0dx0a});x0dx0ax0dx0abuf = new byte[1024];x0dx0atryx0dx0a{x0dx0asocket = new DatagramSocket(1230);x0dx0apacket = new DatagramPacket(buf, buf.length);x0dx0asocket.receive(packet);x0dx0afile = new File(new String(packet.getData()));x0dx0asocket = new DatagramSocket();x0dx0a} x0dx0acatch (Exception e)x0dx0a{e.printStackTrace();x0dx0a}x0dx0ax0dx0aif(file.exists())x0dx0a{x0dx0atryx0dx0a{x0dx0abuf = new byte[(int)file.length()];x0dx0apacket = new DatagramPacket(buf,buf.length,InetAddress.getLocalHost(),1234);x0dx0ainput = new FileInputStream(file);x0dx0ainput.read(buf);x0dx0asocket.send(packet);x0dx0a}x0dx0acatch (IOException e) x0dx0a{x0dx0ae.printStackTrace();x0dx0a}x0dx0a}x0dx0aelsex0dx0a{x0dx0atryx0dx0a{x0dx0apacket = new DatagramPacket(message.getBytes(),message.getBytes().length,x0dx0aInetAddress.getLocalHost(),1234);x0dx0asocket.send(packet);x0dx0a}x0dx0acatch (Exception e) x0dx0a{x0dx0ae.printStackTrace();x0dx0a}x0dx0a}x0dx0ax0dx0a}x0dx0apublic static void main(String[] args)x0dx0a{x0dx0anew N4BT6("Server");x0dx0a}x0dx0a}x0dx0a客戶端：import java.awt.*;x0dx0aimport java.awt.event.*;x0dx0aimport java.net.DatagramPacket;x0dx0aimport java.net.DatagramSocket;x0dx0aimport java.net.InetAddress;public class N4BT6_2 extends Framex0dx0a{x0dx0aTextArea text;x0dx0aString message = "Q.txt";x0dx0aDatagramSocket socket ;x0dx0aDatagramPacket packet;x0dx0abyte[] buf;x0dx0apublic N4BT6_2(String title)x0dx0a{x0dx0asuper(title);x0dx0atext = new TextArea(6,4);x0dx0aadd(text);x0dx0asetSize(400, 300);x0dx0asetVisible(true);x0dx0aaddWindowListener(new WindowAdapter()x0dx0a{x0dx0apublic void windowClosing(WindowEvent e)x0dx0a{x0dx0adispose();x0dx0a}x0dx0a});x0dx0atryx0dx0a{x0dx0ax0dx0asocket = new DatagramSocket();x0dx0apacket = new DatagramPacket(message.getBytes(),message.getBytes().length,x0dx0aInetAddress.getLocalHost(),1230);x0dx0asocket.send(packet);x0dx0a}x0dx0acatch (Exception e) x0dx0a{x0dx0ae.printStackTrace();x0dx0a}x0dx0ax0dx0atryx0dx0a{x0dx0abuf = new byte[1024];x0dx0asocket = new DatagramSocket(1234);x0dx0apacket = new DatagramPacket(buf,buf.length);x0dx0asocket.receive(packet);x0dx0atext.append(new String(buf));x0dx0a}x0dx0acatch (Exception e) x0dx0a{x0dx0ae.printStackTrace();x0dx0a}x0dx0a}x0dx0apublic static void main(String[] args)x0dx0a{x0dx0anew N4BT6_2("Client");x0dx0a}x0dx0a}